Last time I used Authy, you had to sync codes to another device, IIRC. Still, most peoples’ phones have a lot more than just auth codes on them. My warning was meant to address all those other data, too.
But now that I think about it, wiping and rooting a fresh/temporary device, syncing Authy, exporting with Aegis, then importing back to your main device would work…
I feel like the comment was sarcastic. At least, that’s how I read it in my head.